How to Prepare Statistics for SSC   
            CGL Tier II - Study Notes in PDF 
        SSC CGL Tier II Exam will be conducted soon! The SSC CGL Prelims Exam was 
        conducted from 5th August to 24th August 2017. This year the exam pattern for Prelims 
        Exam also went through a lot of chances. There are a total of 4733 vacancies that will be 
        filled this year. If you are confident that you will make it through to the SSC CGL Tier II, 
        then you can read the article given below. This article will help on How to Prepare 
        Statistics for SSC CGL Tier II. In the following article, you will know in detail about 
        Descriptive Statistics, viz. Central Tendency & Dispersion, Mean, Median & Mode, 
        Skewness & Kurtosis, etc. You can also take our SSC CGL Online Mock Tests to boost up 
        your preparation strategy. 
        Descriptive Statistics is the best way to describe and summarize the characteristics of 
        a data set in terms of two of its properties i.e. Central Tendency and Dispersion. 
        Central Tendency - Prepare Statistics for SSC CGL 
        Tier II 
        In order to describe and represent a set of data as a single number, we need measures of 
        central tendency that intended to describe the performance of the group and centre of 
        the data. It also tells us about the shape and nature of the distribution. Measures of 
        central tendency include: 
        Mean: 
        The sum of all the observations divided by the number of observations 
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                             Find the mean of 1, 2, 3, 4, 5, 6, 7, 8, 9                                                                              
                                                              
                    Median: 
                    The score in the middle when the observations are ordered from the smallest to the 
                    largest. If the total number of observations n is an odd number, then the number on the 
                    position is the median. If n is an even number, then the average of the two numbers on 
                    the      and          positions is the median. 
                             o Find the median of 5, 6, 11, 10, 4, 9, 7 
                                   o    4, 5, 6, 7, 9, 10, 11 = 7 
                             o Find the median of 5, 17, 15, 3, 9, 18, 6, 10 
                                   o    3, 5, 6, 9, 10, 15, 17, 18 =                     
                    Mode: 
                    The number that occurs most frequently. If two numbers tie then the observation will 
                    have two modes and is called Bimodal 
                             Find the mode of 2, 6, 3, 9, 5, 6, 2, 6 
                             2, 2, 3, 5, 6, 6, 6, 9 = 6 
                    Relation between Mean, Median and Mode 
                    Mean – Mode = 3 (Mean – Median) 
                    Scales of Measurement:-  
                         1.  Nominal Scale – That can simply be broken down into categories 
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         2.  Ordinal Scale – That can be categorized and can be placed in order or ranking   
         3.  Interval Scale – That can be ranked but has no absolute zero point 
         4.  Ratio Scale – That allows to compare and has meaningful zero values 
       For Nominal scale, the mode is the only measure that can be used. For Ordinal Scale, 
       the mode and the median may be used. For Interval – Ratio Scale, the mean, 
       median and mode all can be used. 
       Partition Values 
       If the samples are arranged in ascending or descending order, then the measures of 
       central tendency divides the observations in two equal parts. In the same way, the given 
       series can be divided into four, ten and hundred equal parts. 
       Quartiles         
       Quartiles divides a series into 4 equal parts i.e. Q1, Q2 and Q3. Q1 is known as first or 
       lower Quartile covering 25% observations. Q2 is known as second Quartile is the same 
       as Median of the series. Q3 is known as third or upper Quartile covering 75% 
       observations. 
                         
       Where, 
       l = lower limit of median class; i = class interval 
       cf = total of all frequencies before median class 
       f = frequency of median class; n = total number of observations 
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               Deciles: - Deciles divides a series into 10 equal parts i.e          etc. 
                                                            
               Where, 
               l = lower limit of median class; i = class interval 
               cf = total of all frequencies before median class 
               f = frequency of median class; n = total number of observations 
               Percentiles: - Percentiles divides a series into 100 equal parts i.e.,
                                        etc. 
                                                                     
               Where, 
               l = lower limit of median class; i = class interval 
               cf = total of all frequencies before median class 
               f = frequency of median class; n = total number of observations 
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